It is well-established that, as a consumer decision aid, electronic word of mouth (eWOM) provides opportunities to both consumers and companies. By relying on eWOM, consumers believe that they are better able to make informed purchase decisions. By incorporating eWOM in their business strategies, companies believe that they can capitalize on its effects. However, both parties must overcome challenges in order to benefit from these opportunities. Consumers are confronted with the challenge of selecting the most useful and credible information amid the overwhelming amount of electronic word of mouth that is circulating on the internet. Companies are faced with the challenge of managing eWOM, especially when they are negatively portrayed in such communications. Although these challenges constitute a topic of both societal and managerial concern, they lack a strong scientific foundation. The objective of this dissertation is therefore to investigate these challenges.